Abstract

The nature and quality of artificial lighting are becoming more and more recognized and debated issues concerning their impact on comfort, well-being and even human’s health (chronobiology). Therefore, the target must be to emulate natural (sun) light for indoor illumination. In this paper parameters which are responsible for the nature and quality of light sources are elaborated. Leading edge high quality light sources, realized by light emitting diodes (LEDs) for emulating natural light, are presented.

The junction temperature of electroluminescence devices is a key parameter which influences emission wavelength, light output (power efficiency), light degradation and lifetime of the LEDs. We present experimental data and a model which allows one to derive the junction temperature of LEDs under operation.